Separating apparatus

ABSTRACT

APPARATUS COMPRISING AN ELONGATED DUCT PROVIDED WITH CURVED ELBOW END PORTIONS AND A STRAIGHT INTERMEDIATE DUCT PORTION THEREBETWEEN HAVING MEANS FOR DEFLECTING PARTICLES TO THE OUTER WALL OF THE DOWNSTREAM CURVED ELBOW AND REMOVING CARRIER MEDIUM FROM THE INNER WALL THEREOF FOR RECEIVING AND SEPARATING PARTICLES FROM A CARRIER MEDIUM WHICH IS CAUSED TO FLOW IN A PRESCRIBED MANNER AT A RELATIVELY HIGH VELOCITY.

Jan. 12,1971 A HU ETAL 3,553,944

SEPARATING APPARATUS Filed Oct. 1. 1968 2 Sheets-Sheet l INVENTORS ALLENHUM HAROLD V. PERTTULA TAKU TSUCHIYA ATTORNEY Jan. 12, 1971 HUM ETAL I ISEPARATING APPARATUS 2 Sheets-Sheet 2 Filed Oct. '1, 1968 wwN INVENTORSATTORNEY United States Patent O 3,553,944 SEPARATING APPARATUS AllenHum, Minneapolis, Minn., Harold V. Perttula, San Jose, Calif., andTakuzo Tsuchiya, Minnneapolis, Minn., assignors to General Mills, Inc.,a corporation of Dela.

ware

Filed Oct. 1, 1968, Ser. No. 764,180 Int. Cl. B01d 45/12 U.S. Cl. 55-267Claims ABSTRACT OF THE DISCLOSURE Apparatus comprising an elongated ductprovided with curved elbow end portions and a straight intermediate ductportion therebetween having means for deflecting particles to the outerwall of the downstream curved elbow and removing carrier medium from theinner wall thereof for receiving and separating particles from a carriermedium which is caused to flow in a prescribed manner at a relativelyhigh velocity.

The present invention relates to a separating apparatus, and moreparticularly to an apparatus for receiving a mobile mixture of productand a carrier medium, separating the product and medium from each other,and discharging them at different points for further processing.

According to the known prior art, various devices and methods are knownfor separating mixtures of solid substances from a carrier medium. Oneof the most well known of such devices for example, is a cone-shapedcyclone separator into which a mixture of particles and gas, such asair, is introduced in such a manner that a spiral is created. Theparticles are discharged through one opening, while the carrier mediumis removed through another opening. It has been found that such deviceshave not always been the most effective and the most satisfactory in allinstances for separating certain mixtures, such as a mixture whichincludes steam.

One object of the present invention is to provide an improved apparatusfor separating particles of material from a carrier medium.

Another object is to provide an apparatus for receiv ing a mobilemixture of particles and a carrier medium, and effectively separatingthe particles from the medium.

A further object is to provide an improved apparatus for continuouslyseparating particles of material from a mixture of said particles and ahigh velocity superheated steam, and removing the particles and steamthrough separate discharge openings for further processing.

Other objects and advantages will become apparent from a considerationof the following specification and accompanying drawings. Beforeproceeding with a detailed description of the invention however, a briefdescription of it will be presented.

Preferably, the apparatus includes an inclined elongate duct havingcurved portions proximate its two ends. The discharge end portion of theapparatus includes two openings, a discharge duct having an openingtherein for removing the particles, and an exhaust opening ofconsiderably larger dimensions which leads to an exhaust duct, forremoving the carrier medium. A negative pressure is applied to theexhaust duct for withdrawing the carrier medium from the apparatus. Theinlet portion of the elongate duct is provided with means for deflectinga mobile mixture of particles and carrier medium from one of the innersurfaces of the duct to an opposite surface. As the mixture flows pastthe exhaust opening in the discharge end portion, the medium loses itsvelocity by expanding within the end portion into the exhaust duct, andthe negative pressure created within the duct sucks the me- 3,553,944Patented Jan. 12, 1971 dium out of the apparatus. As the particles flowthrough the discharge end portion past the exhaust opening, they tend tofollow the surface opposite the surface having the exhaust openingtherein, by centrifugal force. The particles are ultimately dischargedthrough the opening in the discharge duct.

The invention will best be understood by reference to the followingdrawings wherein:

FIG. 1 is a partial side elevational view illustrating the invention;

FIG. 2 is a top plan view of the apparatus illustrated in FIG. 1;

FIG. 3 is an enlarged partial sectional view of the invention;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is a sectional view taken along line 55 of FIG. 3;

FIG. 6 is a sectional view taken along line 66 of FIG. 3; and

FIG. 7 is a perspective view illustrating one part of the apparatus.

FIGS. 1 and 2 illustrate a receiving and separating apparatus designatedgenerally by reference numeral 10. The apparatus includes an elongateduct 12 which is shown as being inclined with respect to a floor, and asprojecting through an opening 14 in a wall 16. While the duct 12 isillustrated as having a rectangular cross-sectional shape, it should berecognized that other shapes might readily be used as well. Moreover, ifpreferred the duct might have a negative slope, or it might be alignedin a horizontal plane.

As illustrated, the elongate duct 12 includes sections 18 and 20attached to each other by appropriate means; a first curved section orportion 22 attached to the section 20 at a first end and having an inletopening 24 therein; and a second curved section or portion 26 attachedto the section 18 which terminates with a discharge duct or end 28having a discharge opening therein, and a curved top surface 25.Preferably, the duct 12, and the curved portions 22 and 26 are alignedwith respect to each other as illustrated in FIG. 1; that is, the curvedportions 22 and 26 project away from the duct in somewhat oppositedirections, and they are all aligned along a straight line, i.e. avertical plane, in this regard note FIG. 2. The purpose of thispreferred arrangement is to assure a smooth flow of the mixture withinthe apparatus in a prescribed manner. It should be recognized of course,that the separate parts or sections could be oriented with respect toeach other to form somewhat different configurations as wel An exhaustduct 30 is attached at one of its ends to the curved portion 26, and itextends through a second opening 32 in the wall 16, Where it isconnected at its other end to a scrubber 34, or other device, forfurther processing the carrier medium removed from the elongate duct 12.As illustrated, an expansion chamber 27 is formed within the curvedsection 26, between the duct and its connection with the exhaust duct30, which is somewhat larger than the duct. As known, scrubbers are usedfor removing dust particles from a carrier medium, as Well as steam, ifsteam is present in the carrier medium.

Appropriate means are provided adjacent the inlet opening 24 forintroducing material into the apparatus. For illustrative purposes, FIG.1 shows a discharge nozzle 36 of a continuous puffing gun 38, of thetype described and illustrated in Pat. No. 3,231,387. Since the puffinggun 38 forms no part of the present invention, it will not be describedin further detail. A mufller 40 and a spacer or adapter 42, areinterposed between the elongate duct 12 and the puffing gun 38. Themuffler 40 can be of the type commonly used with puffing guns of thistype, and will not be described in further detail.

FIGS. 35 illustrate the apparatus in somewhat greater detail. The curvedsection 26 is provided with a top surface or outer wall 44, and a bottomsurface or inner Wall 46 having an opening 48 therein. The opening 48provides a passage into the duct 30. As shown, the duct 30 is attachedto the curved section 26 by flanges 50, and appropriate fastener meanssuch as bolts or rivets. As can be seen, especially in FIG. 5, theopening 48 is quite large when compared to the area of the bottomsurface 46 of the section 26. Curved baffles 52 and 54, formed of aperforated plate, or as a perforated extension of the main duct,partially cover the rear and the front portions of the opening 48respectively. The baffle 52 aids in guiding the product around thecurved portion, and the baffle 54 prevents the product from reboundingback into the exhaust duct 30. If preferred of course, a screen could beplaced over the entire opening. The discharge duct 28 is provided with aplurality of perforations or openings 56, which provide passages to theexterior of the duct.

The exhaust duct 30 is comprised of one or more sections joined togetherto form a passage to the scrubber 34. As depicted in FIG. 3, at leastthe duct portion adjacent to the opening 48 in the section 26, iscovered with insulating material 58. Doors 60 and 62 are provided insection 26 and the exhaust duct 30. respectively, for permitting anoperator to inspect the interior of the apparatus and for cleaningpurposes. An exhaust fan 64 is provided for creating a negative pressurein the exhaust duct 30, so as to suck the carrier medium through theopening 48 and the duct 30.

The section 20 of duct 12 is provided with a top surface 66 and a bottomsurface 68, and it is designed in such a manner that a tapered passageis provided which extends from the end 70 to the end 72 of section 20.As illustrated, the dimension X at the first end 70, is greater than thedimension Y at the second end 72. The section 18 is also provided with atop surface 74 and a bottom surface 76. As shown in FIG. 3, an angle ais formed between the lower surfaces 68 and 76 of the sections 18 and 20respectively. This angle is referred to as the angle of climb, and itsrelative size can vary, depending upon a number of characteristics, suchas the total length of the duct 12, and the velocity of the materialflowing through the duct.

In operation, the apparatus has been used with excellent results forseparating mobile particles from a carrier medium having a substantiallylower density than the particles, such as steam. As an example, whenusing a continuous puffing gun as depicted in Pat. No. 3,231,387, amixture of product such as cereal pellets, and superheated steam, isdischarged from the gun at a high velocity. In many instances it isdesirable, if not necessary, to separate the steam from the productafter it has been discharged from the pufling gun, so that the productcan be further processed. As known, if the steam is not separated fromthe product the product might become soggy, the equipment damp, and theenvironment in the work area quite humid. The present inventioneffectively and efliiciently accomplishes this result.

The superheated steam and the product pass through the nozzle 36 of thepufling gun, through the muffler 40 and the spacer 42, and into theelongate duct 12 through the inlet opening 24. The velocity force of thesteam is sufiicient to carry the product past the cuved portion ofsection 22, through the sections 18 and 20, and into the second curvedportion of section 26, and more specifically, the chamber 27. Asillustrated, the cross-sectional size of the passage becomes smallerfrom the opening 24 into the section 20; this effectively increases thevelocity of the steam and helps to assure that the product flows throughthe elongate duct. As the product passes through the curved portion 22,it initially follows the lower surface 68 of the section 20, bycentrifugal force. As the product passes the angle of climb or formed bythe junction between surfaces 68 and 76 of sections 20 and 18, theproduct is deflected in such a manner that it is transferred adjacent tothe upper surface 74 of section 18 (note the arrows in FIG. 3 whichillustrate the general path followed by the product). The top surface 74of section 18 and the top surface 44 of the curved portion 26 are bothtangent to the curved surface 25, thus effecting a smooth entry into anddischarge from the curved portion 26. As the product passes through thecurved portion 26, it is assured of a smooth continuous flow, and itfollows the top surface or outer wall 44 by centrifugal force until itreaches the discharge duct 28.

As the high velocity steam enters the curved portion 26, it loses itsvelocity by expanding within the chamber 27, and through the opening 48into the duct 30. The negative pressure created by the exhaust fan 64sucks the steam which has a smaller density than the product, into theexhaust duct, therefore withdrawing it from the curved portion 26. Theperforated baffles 52 and 54 aid in minimizing or preventing the productfrom also being drawn into the exhaust duct. The insulation 58 whichcovers the exhaust duct 30 prevents or minimizes the likelihood of steamcondensing within the duct 30.

The suction pressure required in the exhaust duct 30 is dependent uponthe steam pressure, the size of the discharge duct 28, as well as thesize of the exhaust opening 48. Appropriate means (not shown) can beprovided for controlling the pressure created by the fan 64, so as tofit specific operating conditions. A higher suction is required forhigher steam pressures and larger discharge ducts. The amount of suctionshould be regulated so that no steam flows through the discharge duct28. If the duct 28 is too large, higher suction is required; thishowever, might cause product hold-up in the discharge duct 28, thusresulting in a choked condition and/ or the product being dischargedthrough the exhaust opening 48 into the exhaust duct 30 with the steam.On the other hand, if the discharge duct 28 is too small, the productflow might be restricted by friction between the particles, frictionbetween the particles and the duct wall, and by a counterfiow of thesuction air created by the exhaust fan 64. The size of the exhaustopening 48 should also be considered, as it has a minimum arearequirement. If the opening is too small, more suction is required todraw the steam into the exhaust duct 30, this of course increases thelikelihood of product being entrained with the steam passing into theexhaust duct. The above conditions can be at least partially relieved bydrawing the majority of the steam exhaust air through the openings 56 inthe duct 28. Since the velocity of the product is still quite high as itpasses through section 26, there is only a minimum effect on thedischarge of the product through the duct 28.

The physical shape of the apparatus can vary, depending upon a number offactors such as the available space in the work area, and the specificmixture being received and separated. While a rectangularcross-sectional shape of the ducts is illustrated, a square or circularcross-section could be used as well, as pointed out above. As a furthermodification, the steam pick-up could also be a side or top discharge,rather than a bottom discharge as shown; a bottom discharge howeveraffords the least chance of product contamination. If a side or topdischarge is used, it might be necessary to cover the opening with ascreen or similar covering. Since the mixture being handled might beintroduced by different devices, and since its make-up can vary, therelative length of the apparatus, especially duct 12, should be designedand dimensioned to make sure that the mixture flows into the curverdportion 26, as smoothly as possible.

As the product flows through the duct 12, it is deflected within theelongated duct 12 so that it initially follows a path adjacent to thebottom surface 68 of section 20, and then to a path adjacent to theupper surface 74 of section 18. In this manner, the mixture flowssmoothly through the apparatus with a minimum amount of bouncing of theindividual particles against each other, and against the inner surfacesof the elongate duct. If preferred of course, the dimensions of thesections 18 and 20 could be the same, i.e., the angle of climbeliminated. It has been found however, that if the angle of climb a iseliminated, the product does not flow through the apparatus as smoothlyand separation of the product from the steam is not as efiicient. As themixture of product and steam passes into the curved portion 26, theproduct continues proximate the top surface 44 by centrifugal force,whereas the steam expands within the chamber 27, and the duct 30, andthus loses its velocity. The negative pressure created within the duct30 can be readily regulated so that only the steam is removed fromsection 26. The product then flows out through the discharge duct 28where it is processed further or stored for future use.

In the above description and attached drawings, a disclosure of theprinciples of this invention is presented, together with an embodimentwith which the invention might be carried out.

Now, therefore, we claim:

1. Apparatus for separating mobile particles from a carrier mediumcomprising an elongated duct, said duct having a first curved elbowportion at a first end with an inlet opening at one end of the ductforadmitting the particles and medium into the duct, a second curved elbowportion at a second end with a discharge opening therein at the outletend for removing the particles therefrom, said second elbow having innerand outer walls, and a straight portion connected intermediate the elbowportions, the inner wall of said second curved elbow portion having anexhaust opening for removing the carrier medium from the elongated duct,said exhaust opening being spaced upstream from said discharge opening,an exhaust duct, means attaching said exhaust duct to the second curvedelbow portion at said exhaust opening, means connected to said exhaustduct for applying a negative pressure within the duct therebywithdrawing the carrier medium from said second curl/ed elbow portion,and means for deflecting the particles in said elongated duct so thatthey tend to follow the outer wall opposite the exhaust opening.

2. The combination of claim 1 wherein an expansion chamber is formedwithin the second curved elbow portion adjacent the exhaust opening, andthe carrier medium loses its velocity as it expands within said chamberand the exhaust duct, said product being caused to flow through saidsecond curved portion and out through the discharge duct.

3. The combination of claim 1 wherein a discharge duct is connected tothe end of the second curved portion, and a plurality of openings areprovided in said discharge duct wall proximate the discharge opening forpermitting air to be drawn into the second curved elbow portion.

4. The combination of claim 1 wherein means is provided introducing theparticles and carrier medium into the inlet opening of the first curvedelbow portion.

5. The combination of claim 1 wherein the surface of the exhaust ductproximate the second curved portion is covered with an insulatingmaterial.

6. The combination of claim 1 wherein the elongate duct, the firstcurved portion, and the second curved portion lie in substantially thesame plane, and said curved portions project away from the elongate ductin somewhat opposite directions.

7. The combination of claim 6 wherein baffie means is provided over atleast a portion of the exhaust opening in the second curved elbowportion for preventing the particles from entering the exhaust duct.

8. The combination of claim 6 wherein the elongate duct is inclined withrespect to a horizontal plane.

9. The combination of claim 6 wherein the deflection means is providedwithin said elongate duct adjacent the first curved portion.

10. The combination of claim 9 wherein a portion of the elongated ductadjacent said first curved elbow portion has a rectangularcross-sectional shape, one surface of said duct being inclined withrespect to the opposite surface thereby forming a tapered passage whichdeflects the particles toward the outer wall of the second curved elbowportion.

References Cited UNITED STATES PATENTS 532,144 1/1895 Day -461 535,0993/1895 Gale et al 55-461 1,230,757 6/1917 Morrison 55461 1,818,3678/1931 Wallace 55 461 2,221,385 11/1940 Rogers 55-461 FOREIGN PATENTS1,088,435 9/1954 France 55461 FRANK W. LUTTER, Primary Examiner B.NOZICK, Assistant Examiner US. Cl. X.R.

